covert



UNITED STATES PATET OFFICE.

H. W'. COVERT, OF ROCHESTER, NEW' YORK.

LOCK.

Specification forming part of Letters Patent No. 18,228, dated September 15, 1857; Reissued July 12, 1864, No. 1,725.

To all whom t may concern:

Be it known that I, H. IV. OovERT, of the city of Rochester, county of Monroe, and State of New York, have made and invented certain new and useful Improvements in Permutation-Locks, of which the following is a full and accurate description, reference being had to the accompanying drawings, making part of this specification, and to the letters of reference marked thereon, same letters referring to like parts in all the figures.

Of said drawings Figure 1 is a perspective view of my improved lock. Fig. 2 is a section on line O, Q Fig. 3, and Fig. 3 is an elevation of Fig. l-the covering plates being removed.

The nature of this invention consists in an improved method of effecting those changes in a permutation lock which are necessary either to allow or prevent the bolts being thrown, and will be more fully understood from a detailed description of the several parts of the lock and their mode of working.

In the drawings B is the bolt and K the bit of the stationary key which throws said bolt back and forth. On said bolt is a projection (a) and slots (s s) (shown in dotted lines)-the projection (a) passing through the slot seen in the brass tumbler, and the slots (s s) being adapted to receive the tongue T att-ached to said tumbler. The tumbler moves vertically in the case of the lock-having a strong tendency downward owing to the spring O. And it will be at once seen that when the projection (a) lies in either of the notches in the slot in the tumbler, it will be impossible to move the bolt until the tumbler has been raised. Now the bit of the key will raise the tumbler suiiiciently high for this purpose if the tongue T does not prevent it by pressing against the disks D D (Figs. 2 and 3) which it will do unless the notches (Figs. 3 and 4) in both said disks are in line and immediately over the tongue T.

Thus far my lock is substantially the same as most others of its class and it is in the means of bringing the notches in the disks D D into and out of line with the tongue T that my invention consists.

It will be seen that in the center of each of the disks D, D is a frustum of a cone (w) (Figs. 2 and 3) which passes nearly through said disks but projects a little on one side and falls short on the other. Between the disk (D) and the base of the cone (V) lies the steel plate (P) and at the rear of these disks is a plate (P) which may be acted upon by the screw Z so as to press the steel cones into the brass disks (D D) or release them from such pressure as may be desired. In front of said disks is the cylinder (H) carrying the index w which refers to the graduated circle on the face of the lock. `Through this cylinder and the two disks is a circular hole with an extension at the side (as seen in Figs. 1 and 2) which receives a suitable key for the purpose of turning the disks around. It is now evident that (whatever be the position of the disks) if the key be inserted into the cylinder H and pressedv steadily in while being turned around it will fall into the hole in the first disk, and the same operation repeated will introduce the key into the last disk. If now we turn the key around it is evident that this last disk may be brought into any required position; and if while in this position we withdraw the key it will be left in that position, and the same of the next disk. And it is further evident that as the side extension of the holes in the cylinder (H) and the several disks must coincide in order to admit the key the position of the index on this cylinder may be made to indicate accurately the position of the notches (n) in the several disks (D, D,) and consequently if we know the required positions of said disk in order to bring the notches in all the disks into line with the tongue T we have it in our power to open the lock. But as it is necessary to change the position of the notches (n) in the disks with regard to the index on the front cyl inder (so that those alone who are in the secret may be able to open the lock) the following method is pursued:

The disks having been all rendered perfectly immovable by hinging them into line and elevating the tongue T by throwing the bolt half way; the screw Z is loosed so that the steel cones (o o) may be easily turned around. Then the cone farthest in is turned around (and with it all the other cones and the outer cylinder too) as desired and the position of the indeX with regard to the graduated circle on the front plate noted. The key is then withdrawn so as no longer to affect this cone in its revolution and the next one is treated in the same manner, and so on throughout the series if more than two disks be used. The back screw is then tightened when the steel cone will be so rmly fixed into the brass disks as no longer to permit any movement between them. Anew combination is thus produced which may be used as previously described.

Instead of the screw (Z) and the conical bearings of the parts (lv v) it is obvious that plain cylinders may be used and a separate screw for each-the screws in this case passing through the disks themselves or their hubs and pressing on the cylinder so as to retain them in place. And in order to retain the disks more irmly and steadily in place while forming a new combination as previously described I insert the pin (R) through the outer case and two disks as shown in red lines in F ig. 2. By means of this pin also we can bring the disks into a position to allow of the opening of the lock if we should happen to forget the combination while the door is open. For by inserting the pin in the case and pressing it forward while the disks are being slowly revolved it will fall into the hole in the rst disk. And if we now draw the key out of this first disk and revolve the second we can pass the pin through it too and we can then open the lock as the hole through which the pin passes both in the case and the disks must be originally bored while the lock was in position Jfor that purpose.

The advantages arising from this arrangement are numerous and important. Not only is the whole lock simple and easily constructed-it is also free from any danger of fracture by blows or otherwise-there being no part exposed which can be injured by ordinary violence. Its compactness is also very great so that a very strong lock may be applied toa comparatively small door without being disproportioned to it. And above all the number of changes which may be produced is almost unlimited, as a difierence in posit-ion in the cones or cylinders and disks may be eiected to a degree the minuteness of which is limited only by our powers of vision and which will amply serve the purposes of a new combination. In other forms where the connect-ion between the part to receive the key and that to receive the tongue T is eiiected by means of cogs or gearing the number of charges is limited to the number of teeth in the wheels or disks. The importance of this feature 4requires no comment.

Having thus described my invention what I claim therein as new and desire to secure by Letters Patent is- The combination of the disks D, D, with the cones, cylinders or disks (o, o) in the manner and for the purpose substantially as described.

H. W. COVERT.

Vitnesses:

Jol-IN PHIN, A. K. AMsDEN.

[Fms'r PRINTED 1912.] 

